Chris@1536: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@1536: 
Chris@1536: /*
Chris@1536:     Sonic Visualiser
Chris@1536:     An audio file viewer and annotation editor.
Chris@1536:     Centre for Digital Music, Queen Mary, University of London.
Chris@1536:    
Chris@1536:     This program is free software; you can redistribute it and/or
Chris@1536:     modify it under the terms of the GNU General Public License as
Chris@1536:     published by the Free Software Foundation; either version 2 of the
Chris@1536:     License, or (at your option) any later version.  See the file
Chris@1536:     COPYING included with this distribution for more information.
Chris@1536: */
Chris@1536: 
Chris@1536: #include "WaveformOversampler.h"
Chris@1536: 
Chris@1544: #include "base/Profiler.h"
Chris@1544: 
Chris@1536: #include "data/model/DenseTimeValueModel.h"
Chris@1536: 
Chris@1536: floatvec_t
Chris@1745: WaveformOversampler::getOversampledData(const DenseTimeValueModel &source,
Chris@1536:                                         int channel,
Chris@1536:                                         sv_frame_t sourceStartFrame,
Chris@1536:                                         sv_frame_t sourceFrameCount,
Chris@1536:                                         int oversampleBy)
Chris@1536: {
Chris@1544:     Profiler profiler("WaveformOversampler::getOversampledData");
Chris@1544:     
Chris@1536:     // Oversampled at a fixed ratio of m_filterRatio
Chris@1536:     floatvec_t fixedRatio = getFixedRatioData(source, channel,
Chris@1536:                                               sourceStartFrame,
Chris@1536:                                               sourceFrameCount);
Chris@1536:     sv_frame_t fixedCount = fixedRatio.size();
Chris@1536:     sv_frame_t targetCount = (fixedCount / m_filterRatio) * oversampleBy;
Chris@1536: 
Chris@1536:     // And apply linear interpolation to the desired factor
Chris@1536:     
Chris@1536:     floatvec_t result(targetCount, 0.f);
Chris@1536: 
Chris@1536:     for (int i = 0; i < targetCount; ++i) {
Chris@1536:         double pos = (double(i) / oversampleBy) * m_filterRatio;
Chris@1536:         double diff = pos - floor(pos);
Chris@1536:         int ix = int(floor(pos));
Chris@1538:         double interpolated = (1.0 - diff) * fixedRatio[ix];
Chris@1536:         if (in_range_for(fixedRatio, ix + 1)) {
Chris@1536:             interpolated += diff * fixedRatio[ix + 1];
Chris@1536:         }
Chris@1538:         result[i] = float(interpolated);
Chris@1536:     }
Chris@1536: 
Chris@1536:     return result;
Chris@1536: }
Chris@1536: 
Chris@1536: floatvec_t
Chris@1745: WaveformOversampler::getFixedRatioData(const DenseTimeValueModel &source,
Chris@1536:                                        int channel,
Chris@1536:                                        sv_frame_t sourceStartFrame,
Chris@1536:                                        sv_frame_t sourceFrameCount)
Chris@1536: {
Chris@1544:     Profiler profiler("WaveformOversampler::getFixedRatioData");
Chris@1544:     
Chris@1745:     sv_frame_t sourceLength = source.getEndFrame();
Chris@1536:     
Chris@1536:     if (sourceStartFrame + sourceFrameCount > sourceLength) {
Chris@1536:         sourceFrameCount = sourceLength - sourceStartFrame;
Chris@1536:         if (sourceFrameCount <= 0) return {};
Chris@1536:     }
Chris@1536: 
Chris@1536:     sv_frame_t targetFrameCount = sourceFrameCount * m_filterRatio;
Chris@1536:     
Chris@1536:     sv_frame_t filterLength = m_filter.size(); // NB this is known to be odd
Chris@1536:     sv_frame_t filterTailOut = (filterLength - 1) / 2;
Chris@1538:     sv_frame_t filterTailIn = filterTailOut / m_filterRatio;
Chris@1536: 
Chris@1536:     floatvec_t oversampled(targetFrameCount, 0.f);
Chris@1536: 
Chris@1536:     sv_frame_t i0 = sourceStartFrame - filterTailIn;
Chris@1536:     if (i0 < 0) {
Chris@1536:         i0 = 0;
Chris@1536:     }
Chris@1536:     sv_frame_t i1 = sourceStartFrame + sourceFrameCount + filterTailIn;
Chris@1536:     if (i1 > sourceLength) {
Chris@1536:         i1 = sourceLength;
Chris@1536:     }
Chris@1538:     
Chris@1745:     floatvec_t sourceData = source.getData(channel, i0, i1 - i0);
Chris@1536:     
Chris@1536:     for (sv_frame_t i = i0; i < i1; ++i) {
Chris@1536:         float v = sourceData[i - i0];
Chris@1536:         sv_frame_t outOffset =
Chris@1536:             (i - sourceStartFrame) * m_filterRatio - filterTailOut;
Chris@1536:         for (sv_frame_t j = 0; j < filterLength; ++j) {
Chris@1536:             sv_frame_t outIndex = outOffset + j;
Chris@1536:             if (outIndex < 0 || outIndex >= targetFrameCount) {
Chris@1536:                 continue;
Chris@1536:             }
Chris@1536:             oversampled[outIndex] += v * m_filter[j];
Chris@1536:         }
Chris@1536:     }
Chris@1536: 
Chris@1536:     return oversampled;
Chris@1536: }
Chris@1536: 
Chris@1536: int
Chris@1536: WaveformOversampler::m_filterRatio = 8;
Chris@1536: 
Chris@1536: /// Precalculated windowed sinc FIR filter for oversampling ratio of 8
Chris@1536: floatvec_t
Chris@1536: WaveformOversampler::m_filter {
Chris@1536:     2.0171043153063023E-4, 2.887198196326776E-4,
Chris@1536:     3.410439309101285E-4, 3.4267123819805857E-4,
Chris@1536:     2.843462511901066E-4, 1.6636986363946504E-4,
Chris@1536:     -4.5940658605786285E-18, -1.9299665002484582E-4,
Chris@1536:     -3.8279951732549946E-4, -5.357990649609105E-4,
Chris@1536:     -6.201170748425957E-4, -6.11531555444137E-4,
Chris@1536:     -4.987822892899791E-4, -2.872272251922189E-4,
Chris@1536:     -7.822991648518709E-19, 3.2382854144162815E-4,
Chris@1536:     6.341027017666046E-4, 8.769331519465396E-4,
Chris@1536:     0.001003535186382615, 9.791732608026272E-4,
Chris@1536:     7.906678783612421E-4, 4.5101220009813206E-4,
Chris@1536:     -3.039648514978356E-18, -4.996532051508215E-4,
Chris@1536:     -9.704877518513666E-4, -0.0013318083550190923,
Chris@1536:     -0.0015128911871247466, -0.0014658111457301016,
Chris@1536:     -0.0011756800671747431, -6.663214707558645E-4,
Chris@1536:     1.0713650598357415E-17, 7.292959363289514E-4,
Chris@1536:     0.0014084768982220279, 0.0019222969998680237,
Chris@1536:     0.0021721723797956524, 0.0020938999751673173,
Chris@1536:     0.0016712330766289326, 9.427050283841188E-4,
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Chris@1536:     -5.1499690577098E-18, 0.0013904094522721,
Chris@1536:     0.0026648961861419334, 0.0036103002009868065,
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Chris@1536:     0.004579613038976446, 0.006174912111845945,
Chris@1536:     0.00689578873526276, 0.006571541332393174,
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Chris@1536:     0.007388553022623823, 0.009931080628244226,
Chris@1536:     0.011056594746806033, 0.010505398026651453,
Chris@1536:     0.008267906564613223, 0.00460048159140493,
Chris@1536:     -1.816145184081109E-17, -0.004861124757802925,
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Chris@1536:     -0.01378467517229709, -0.013084177592430083,
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Chris@1536:     0.011445734103106982, 0.015355551390625357,
Chris@1536:     0.017065088242935025, 0.016186450815185452,
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Chris@1536:     0.0173729814451255, 0.023294901939595228,
Chris@1536:     0.02587678878709242, 0.02453592568963366,
Chris@1536:     0.01927365323131565, 0.010706050935569809,
Chris@1536:     -2.8133472199037193E-17, -0.011280308241551094,
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Chris@1536:     3.042099156841831E-17, 0.013951594368737923,
Chris@1536:     0.0264884258371512, 0.03556693609945249,
Chris@1536:     0.03957036852169639, 0.0375845888664677,
Chris@1536:     0.029579845398822833, 0.016465167405787955,
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Chris@1536:     -0.03315356952091943, -0.04460179422099746,
Chris@1536:     -0.0497244634100025, -0.04733366619358394,
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Chris@1536:     -3.5992766927138734E-17, -0.029168755716052385,
Chris@1536:     -0.055960213335110184, -0.07598693477350407,
Chris@1536:     -0.08556575102599769, -0.08233350786406181,
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Chris@1536:     0.07882920057770397, 0.10826166115536123,
Chris@1536:     0.12343378955977465, 0.12040455825217859,
Chris@1536:     0.09755344650130694, 0.056053367635801106,
Chris@1536:     -3.8215953158245473E-17, -0.0638435745677513,
Chris@1536:     -0.12667849902789644, -0.17861887575594584,
Chris@1536:     -0.20985333136704623, -0.21188193950868073,
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Chris@1536:     3.8789099095340224E-17, 0.13868670259490817,
Chris@1536:     0.29927055936918734, 0.46961864377510765,
Chris@1536:     0.6358321371992203, 0.7836674214332147,
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Chris@1536:     1.0000000000000004, 0.9744199685311685,
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Chris@1536:     0.6358321371992203, 0.46961864377510765,
Chris@1536:     0.29927055936918734, 0.13868670259490817,
Chris@1536:     3.8789099095340224E-17, -0.10760048593620072,
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Chris@1536:     0.09755344650130694, 0.12040455825217859,
Chris@1536:     0.12343378955977465, 0.10826166115536123,
Chris@1536:     0.07882920057770397, 0.04066438975848791,
Chris@1536:     3.727625511036616E-17, -0.03713224848702707,
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Chris@1536: };
Chris@1536: